Chromatographic separations used for protein purification are traditionally performed in batch mode, i.e. a single packed column is used and equilibration, load, wash, elution and regeneration/cleaning are performed sequentially. This mode leads to a comparatively long process with fairly low overall throughput. In addition, due to kinetic limitations of protein adsorption, in a batch mode, chromatography columns are loaded only to their so-called dynamic capacity which usually is 30 to 50% of their equilibrium capacity. This in turn requires using columns of two to three times the volume than would be needed if the columns were operated in equilibrium. Since protein chromatography resins are very expensive, this has major economic consequences adding to the cost of purification of product. Additionally, wash and elution processes in batch column chromatography require substantial fluid volumes, which is also due to the batch mode of operation which has economic consequences since the purified water used must be specially treated.
Simulated Moving Bed (SMB) chromatography has been used in the petrochemical and mineral industries. SMB chromatography has also found application in the pharmaceutical industry for the separation of enantiomers.
Other applications of SMB chromatography include, for example, the separation of fructose from fructose-glucose solutions and the separation of sucrose from sugar beet or sugar cane syrups. Solution components are differentially absorbed by the ion exchange resin so that a separation waveform develops within the simulated moving bed.